Develop Reference

Newbie> How can I search and array for a promted word<

I am trying to learn JS and found this "test" but cant figure it out.
I have an array and I need to search through if there are words that start with "syn". I tried few options but nothing worked for me. This I think is the closest Ive got but it still returns empty array. I just needs to be from the start of the word(not in the middle). Can someone please help me?
const data = [
'Synáček',
'Alois, synové a bratři',
'Autosynchro',
'Sy-noid',
'Brak a synopie',
'Brambory',
'Syntetika'
];
let vyraz = prompt('Výraz', null);
var hledat = [];
for (var i = 0; i < data.lenght; i++) {
if (data.lowerCase[i].includes == vyraz.lowerCase) {
hledat.push(data[i])
}
};
console.log(hledat);

You have some errors in your code. This is how it should be:
for (var i = 0; i < data.length; i++) {
if (data[i].toLowerCase().startsWith(vyraz.toLowerCase())){
hledat.push(data[i])
}
};
console.log(hledat);
Note that you had a typo in data.length. Also the method to transform to lower case is toLowerCase instead of lowerCase and you forgot the parenthesis after the function calls. includes is a method not a property so using it like someString.includes == something is not correct. Also in data.lowerCase[i] the array index must come after the array like in data[i].toLowerCase().

You could use .filter() method with a regex.
const data = [
'Synáček',
'Alois, synové a bratři',
'Autosynchro',
'Sy-noid',
'Brak a synopie',
'Brambory',
'Syntetika'
];
const result = data.filter(item => item.toLowerCase().match(/^syn|\ssyn/));
console.log(result);

Array index out of bounds in Angular 2

I want to declare an Array with 4 dimensions, then loop some stuff with for() - and then the program breaks. Here is my code:
Typescript:
MoarInfo: any = [[[[]]]];
JavaScript:
constructor(){
for(var i = 0; i < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth].length; i++){
for(var a = 0; a < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i].length; a++){
for(var b = 0; b < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a].length; b++){
this.MoarInfo[i][a][b][0] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][0];
this.MoarInfo[i][a][b][1] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][1];
this.MoarInfo[i][a][b][2] = 'DetailsSpan';
}
}
}
}
The Problem definitively lies at the MoarInfo[][][][] array. I tested my code without it, and it works fine. I tried the following possibilities for the Typescript array declaration as well:
Moarinfo: any[]; MoarInfo = []; MoarInfo = [[[[]]]]; MoarInfo: any[][][][] = [[[[]]]];
And in JavaScript, I tried to declare a new Array, and then push some elements on the MoarInfo array, with different functions (split, unshift, push, concat) and nothing worked.
What am I doing wrong?

Check the size of this.MoarInfo[i][a][b]. You are trying to get the value by index 0,1,2. Looks like its size is less than 2 which is causing this error.
if(this.MoarInfo[i][a][b].size > 0){
this.MoarInfo[i][a][b][0] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][0];
}
if(this.MoarInfo[i][a][b].size > 1){
this.MoarInfo[i][a][b][1] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][1];
}
if(this.MoarInfo[i][a][b].size > 2){
this.MoarInfo[i][a][b][2] = 'DetailsSpan';
}

Okay, I figured it out for myself. You have to set the elements of the dimensions from the array at first blank, then you can fill them with content. First I declared an Array in TypeScript like this AnArray = [];. Then I switched to JavaScript ( to the constructer() function ) and filled it with blank elements. I archieved this with this.AnArray.push();. If you want to set elements for the first dimension use push([]);, if you want an element for the 4th dimension, use push([[[]]]);. And you can set your content space like this push([[['E1',0,0,'E2']]]);. Now you can use follwing syntax:
alert( this.AnArray[0][0][0][3] ); //returns 'E2'
The complete code from my project now works fine and looks like this:
for(var i = 0; i < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth].length; i++){
this.test.push([[[]]]);
for(var a = 0; a < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i].length; a++){
this.test[i].push([[]]);
for(var b = 0; b < this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a].length; b++){
this.test[i][a].push(['',0,'']);
this.test[i][a][b][0] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][0];
this.test[i][a][b][1] = this.AllDataInfo[this.KontoAktuellYearIndex][this.KontoAktuellMonth][i][a][b][1];
this.test[i][a][b][2] = 'DetailsSpan';
}
}
}
I wonder if there is a better way than using arrays, but if you want it too, you can do it like this.
cheers

Using Javascript Array Filter method to apply logic [duplicate]

I have search through quite a lot of questions here, but havent found one that i think fits my bill, so if you know of one please link to it.
I have an array that i want to search through for a specific number and if that number is in the array, i then want to take an action and if not then another action.
I have something like this
var Array = ["1","8","17","14","11","20","2","6"];
for(x=0;x<=Array.length;x++)
{
if(Array[x]==8)
then change picture.src to srcpicture1
else
then change picture.src to srcpicture2
}
but this will run the lenght of the array and end up checking the last element of the array and since the last element is not 8 then it will change the picture to picture2.
Now i can see why this happens, i just dont have any ideas as to how to go about checking if an array contains a specific number.
Thanks in advance.

What you can do is write yourself a function to check if an element belongs to an array:
function inArray(array, value) {
for (var i = 0; i < array.length; i++) {
if (array[i] == value) return true;
}
return false;
}
And the just do:
var arr = ["1","8","17","14","11","20","2","6"];
if (inArray(arr, 8)) {
// change picture.src to srcpicture1
} else {
// change picture.src to srcpicture2
}
It's a lot more readable to me.
For extra points you can add the function to the array prototype like so:
Array.prototype.has = function (value) {
for (var i = 0; i < this.length; i++) {
if (this[i] === value) return true;
}
return false;
};
And then the call would be
if (arr.has(8)) // ...
Pushing this even further, you can check for indexOf() method on array and use it - if not - replace it with the code above.
P.S. Try not to use Array for a variable name, since it's reserved for the actual array type.

use this
http://developer.mozilla.org/En/Core_JavaScript_1.5_Reference/Objects/Array/IndexOf
ie version
https://developer.mozilla.org/En/Core_JavaScript_1.5_Reference/Objects/Array/IndexOf#Compatibility

Why don't just you abort the loop when you find the right number :
for(x=0;x<=Array.length;x++)
{
if(Array[x]==8) {
//change picture.src to srcpicture1
break;
}
}

You could sort the array first then check the array only up to the point at which a number would be in the array, were it to exist.

If you have unique keys and a faster retrieval is what you care about a lot, you can consider using a map instead of an array (if there's a hard-bound case of using an array, then it won't work of course). If using a map, you just check "if( num in arr ) ".

Using .push stops for loop from executing

I have a for loop that suddenly stops working when I try to push to an array. The best way to describe what's going on is just to show my code and try an explain what's going on.
for (var i = 0; i < childs.length; i++) {
if (childs[i].length > 0) {
for (var j = 0; j < amountsValue[i].options.custValues.length; j++) {
var label = amountsValue[i].options.custValues[j].label;
var value = amountsValue[i].options.custValues[j].value;
for (var k = childs[i].length - 1; k >= 0; k--) {
if (childs[i][k].attributes[label] != value) {
childBackup.push(childs[i][k]);
childs[i].splice(k, 1);
}
}
}
amountsValue[i].id = childs[i][0].attributes.internalid;
childs.push(childBackup);
}
}
What's happening is I am looping through an array of items which may or may not have custom options available such as different sizes or colours. The loop will check to see if there are any then get the value and label from the array.
After this, we then loop again to try and match up the values with option values stored within a separate model. The plan is to check if the value is the same as the one stored and if not then splice it from the array. The process of elimination should eventually leave only one option left and that will be used to get the internalid.
During this a back up of the spliced objects is kept so that they can be appended to the array again so that the user can change the option they want. The problem is using childs.push(childBackup) stops the browser form reading the options on amountsValue. This works if the code is removed or it is pushed into another index so I'm really not sure why it isn't working.
Does anyone have any suggestions on how to get this working? I'm sorry if this doesn't make much sense, I've tried to explain it as best I can but let me know if anything needs to be cleared up.
EDIT: I have fixed the issue. Thank you to everyone who suggested ways to solve the problem. As others said, I was trying to manipulate the array I was looping through and changing the length on it. So that part of the code was taken outside the loop and after the initial loop another loop was set up which contained the following code:
for (var i = 0; i < childBackup.length; i++) {
childs[0].push(childBackup[i]);
}
It now works as intended. Thank you.

You are manipulating the array you are looping through.
var count = childs.length;
for (var i = 0; i < count; i++) {
if (childs[i].length > 0) {
for (var j = 0; j < amountsValue[i].options.custValues.length; j++) {
var label = amountsValue[i].options.custValues[j].label;
var value = amountsValue[i].options.custValues[j].value;
for (var k = childs[i].length - 1; k >= 0; k--) {
if (childs[i][k].attributes[label] != value) {
childBackup.push(childs[i][k]);
childs[i].splice(k, 1);
}
}
}
amountsValue[i].id = childs[i][0].attributes.internalid;
childs.push(childBackup);
}
}

JavaScript array sort(function) to sort table rows- not sorting

I am trying to sort a dynamically constructed table on the client side. So far I have done my research to discover JavaScript's sort() method will take a callback. Here is what I have so far:
function retrvCatalog(e){
var merch = document.getElementById('merch');
var tRows = merch.rows;
var tBody = merch.tBodies;
var rowArr = [];
for (x in tRows){
rowArr[x] = tRows[x];
}
rowArr.sort(function(a, b){
if (a.cells.textContent < b.cells.textContent){
return -1;
}
if(a.cells.textContent > b.cells.textContent){
return 1;
}
return 0;
});
}
Stepping through it in Firebug, it appears to not change the order of the rows. Can someone please help me figure out what I am missing?
FINAL ALGORITHM
function retrvCatalog(e){
var fltr = e.id;
var merch = document.getElementById('merch');
var tblHead = merch.tHead;
merch.deleteTHead();
var tRows = merch.rows;
var rowArr = [];
for (var i=0; i<tRows.length; i++){
rowArr[i] = tRows[i];
}
rowArr = rowArr.sort(function(a, b){
if (fltr > 3){
a = parseFloat(a.cells[fltr].innerHTML);
b = parseFloat(b.cells[fltr].innerHTML);
}
else{
a = a.cells[fltr].innerHTML;
b = b.cells[fltr].innerHTML;
}
if (a>b){
return 1;
}
if(a<b){
return -1;
}
return 0;
});
while(merch.hasChildNodes()) {
merch.removeChild(merch.firstChild);
}
merch.appendChild(tblHead);
for (i=0;i<rowArr.length;i++){
merch.appendChild(rowArr[i]);
}
}
The final two columns in the row are numbers, so that is why the method to sort is slightly variable.

Several problems in your code.
First, you didn't declare the x variable.
for(var x...
Second, don't use for-in to iterate an array like collection. Use for.
for (var x = 0, len = tRows.length; x < len; x++){
rowArr[x] = tRows[x];
}
Third, there is no textContent property of a cells collection.
This is easy to test by logging its value. This should have been the first thing you tried.
console.log(a.cells.textContent); // undefined
You need to decide which cell you want, and ask for it by index.
console.log(a.cells[0].textContent);
Finally, you should be aware that this technique will not show the result of the sorting in the DOM. You're only sorting the Array. You'll need to append the new ordering to the DOM.
Maybe you knew this, but you didn't show it in your code.
I don't know the relationship of the rows to the tBodies, so I can't give an example. But if all the rows are in one tbody, just loop the Array, and tBody[0].appendChild(rowArr[i])

I'm not sure if I'm missing something, but I'm pretty sure you can't use textContent on the cells array. You need to index cells so you know which column to actually sort on. If your rows have 4 columns each (or even if there's only 1), you still need to tell the sort function which column to sort on.
So in your sort function, if you wanted to sort by the second column, you'd want something like:
rowArr.sort(function (a, b) {
if (a.cells[1].textContent < b.cells[1].textContent) {
return -1;
} else if (a.cells[1].textContent > b.cells[1].textContent) {
return 1;
}
return 0;
});
And I'm not sure what's in your cells, but you may want to use .innerHTML, not .textContent.

rowArr.sort(function(a,b) {
a = parseFloat(a.cells.textContent);
b = parseFloat(b.cells.textContent);
return (a-b);
};

"don't use for-in to iterate an array like collection." - user1673729
tRows is not an array, it's an HTML collection. That is why I used "for in" – nodirtyrockstar
An HTML Collection is an array like collection. Do not use for-in.